The demographics of patients suffering valvular disease are broad and the treatment modalities for each are complex. Historically, patients younger than 65 years of age have received mechanical valves, while older patients have received bioprosthetic valves. A new demographic of prosthetic valve recipients has emerged recently, namely, the old, sick, inoperable patient who previously would not be a candidate for surgical implantation of a prosthetic valve. These patients are now candidates for a relatively new type of prosthetic valve, i.e., the percutaneously implantable valve (PIV). The PIV is configured like an endovascular stent, except with a tissue valve sewn in the lumen. Like the endovascular stent, the PIV is balloon expandable or self-expanding, and is delivered by way of a catheter to the operative site, where it is deployed and the delivery system removed. The principal advantage of a PIV is that it avoids open-heart surgery. The old, sick patients who would otherwise not survive open heart surgery, can now benefit from the PIV.
Because of a number of design constraints, PIV's are expected to be less durable and are likely to wear out sooner than conventional, surgically implantable valves. Although PIVs are intended for the old, sick patients who have a relatively short life expectancy, there may be instances in which the patient outlives the functional lifespan of the PIV. Therefore, when the PIV ceases to function, it must be replaced.
One potential solution to replacement of a PIV is to insert a new PIV inside the pre-existing PIV. In the field of interventional cardiology, this replacement process is referred to as “restenting.” Restenting a PIV invariably leads to a reduction of effective orifice area of the prosthetic valve, since the old metal cage and worn-out calcified leaflets remain in place and the new PIV is smaller than the pre-existing PIV in order to allow it to be inserted into the remaining lumen. Depending on the original size of the first PIV, and the degree of calcification and obstruction, restenting with another PIV may not lead to an effective orifice area that is compatible with good cardiac function.
As indicated above, there may be instances where an old, worn-out PIV will need to be replaced. Currently, the only means of replacing an old, worn-out, fibrosed PIV is through open heart surgery. Since the patient likely received the PIV because they were not a candidate for open-heart surgery and implantation of a conventional bioprosthesis, the patient is unlikely to be a candidate for open heart surgery to replace a worn or failed PIV. Therefore, non-surgical removal of the existing PIV is a preferred option.
In view of the issues discussed above, the concept of a system for the removal of an old and/or failed PIV becomes very desirable. The present invention provides a method and apparatus for non-surgical removal of a PIV, and includes a set of tools comprising a valve holding tool, a cutting tool and a valve removal tool that facilitate removal of the PIV through the apex of the heart.